The invention is a pumping apparatus which is an energy recovering hydraulic system, capable of an infinite variety of adjustments to meet optimum pumping efficiency necessary to operate a specific well.
The most typical prior art apparatus used to pump fluids, such as oil, is a conventional pumping unit or jack which comprises a gear driven beam or crank, counterbalanced by individual weights. The counterweights are intended to counterbalance the forces directed to the pumping unit from the well.
The heart of the conventional counterweighted pumping unit is the main gear used to drive the beam or crank. Frequently field conditions make it difficult to provide adequate maintenance to the pumping unit. If there is a lack of servicing, the main gear commonly fails, requiring expensive and frequent overhauling of the pumping unit.
Furthermore, the conventional pumping unit is generally expensive to purchase and cumbersome to set up and install. Because the unit must be installed in a proximate position to the well-head, it is reliant on the structure of the surrounding ground for its support, thereby necessitating the installation of a pad to provide the necessary stability. Complete installation of the conventional pumping unit frequently requires the use of a pole truck, servicing rig and many expensive man-hours.
Another known pumping apparatus is the natural gas pumper. This type of pumping apparatus uses the natural gas pressure from the well to assist in operating the pumper. This mode of pumping apparatus cannot operate if the given well is low on gas pressure.
There are other known hydraulic pumping apparatus currently in use. However, these units generally require a service rig or pole truck to install and maintain. The known hydraulic pumpers generally dissipate the energy needed to operate the hydraulic cylinder and do not operate in an energy recovering mode. Many of these pumpers further use a fixed displacement pump, thereby eliminating the ability to adjust the pumping speed in an energy efficient manner.
The pumping apparatus of the present invention eliminates many of the above-mentioned problems by use of a fully adjustable energy recovering hydraulic system to be described fully in the specification below.